The tape carrier bonding is generally made as follows.
First, a sheet of copper foil is laminated on a substrate of cinema film such as polyimide film having perforations. Then the laminated sheet of copper foil is photo-etched to pattern predetermined lead forms, and the copper foil wiring having the predetermined lead form is either Au plated or Sn plated. A TAB tape carrier is prepared in this way and then, an IC chip having Au bumps or Sn-Pb (solder) bumps is laid on the copper foil wiring of the TAB tape carrier, and the inner lead bonding of the TAB tape carrier made by pressure heating with bonding tools. After that, the TAB tape carrier is positioned in an outer bonder, in accordance with a long lead frame, and the IC chip is punched out from the TAB tape carrier and mounted to the lead frame by heat bonding or welding.
For the copper foil wiring of the TAB film tape, electrolytic copper has been mainly used in the past, taking the facility of etching into account.
However, the electrolytic copper is generally weak with respect to repeat fatigue, and so copper foil wiring made of electrolytic copper is broken when TAB type semiconductors such as the thin mounting type or high-density mounting type are given temperature cycle tests for more than a few hundreds of cycles. Thus, it has been a problem that the lifetime of the copper foil wiring made of electrolytic copper is very short.